diff mbox series

[v4,07/10] mm/gup: change index type to long as it counts pages

Message ID 20201217185243.3288048-8-pasha.tatashin@soleen.com
State Superseded
Headers show
Series [v4,01/10] mm/gup: don't pin migrated cma pages in movable zone | expand

Commit Message

Pasha Tatashin Dec. 17, 2020, 6:52 p.m. UTC
In __get_user_pages_locked() i counts number of pages which should be
long.

Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
---
 mm/gup.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Michal Hocko Dec. 18, 2020, 9:50 a.m. UTC | #1
On Thu 17-12-20 13:52:40, Pavel Tatashin wrote:
> In __get_user_pages_locked() i counts number of pages which should be

> long.


Do we know of any caller who would like to pin so many pages it wouldn't
fit into an int? I suspect this is more to sync types of nr_pages and
the iterator right. It would be better to be explicit about this in the
changelog.

> Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>


Acked-by: Michal Hocko <mhocko@suse.com>


> ---

>  mm/gup.c | 2 +-

>  1 file changed, 1 insertion(+), 1 deletion(-)

> 

> diff --git a/mm/gup.c b/mm/gup.c

> index 591d8e2dfc70..1ebb7cc2fbe4 100644

> --- a/mm/gup.c

> +++ b/mm/gup.c

> @@ -1481,7 +1481,7 @@ static long __get_user_pages_locked(struct mm_struct *mm, unsigned long start,

>  {

>  	struct vm_area_struct *vma;

>  	unsigned long vm_flags;

> -	int i;

> +	long i;

>  

>  	/* calculate required read or write permissions.

>  	 * If FOLL_FORCE is set, we only require the "MAY" flags.

> -- 

> 2.25.1


-- 
Michal Hocko
SUSE Labs
Pasha Tatashin Dec. 18, 2020, 12:32 p.m. UTC | #2
On Fri, Dec 18, 2020 at 4:51 AM Michal Hocko <mhocko@suse.com> wrote:
>

> On Thu 17-12-20 13:52:40, Pavel Tatashin wrote:

> > In __get_user_pages_locked() i counts number of pages which should be

> > long.

>

> Do we know of any caller who would like to pin so many pages it wouldn't

> fit into an int? I suspect this is more to sync types of nr_pages and

> the iterator right. It would be better to be explicit about this in the

> changelog.


It is to sync types. I will add it to the changelog.

But, in general 32-bit increasingly becomes too small for handling
page count proportional values. It is 8T for npages. For pinning may
be a bit too large today, but I can image RDMA this size in the
future.

>

> > Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>

>

> Acked-by: Michal Hocko <mhocko@suse.com>

>

> > ---

> >  mm/gup.c | 2 +-

> >  1 file changed, 1 insertion(+), 1 deletion(-)

> >

> > diff --git a/mm/gup.c b/mm/gup.c

> > index 591d8e2dfc70..1ebb7cc2fbe4 100644

> > --- a/mm/gup.c

> > +++ b/mm/gup.c

> > @@ -1481,7 +1481,7 @@ static long __get_user_pages_locked(struct mm_struct *mm, unsigned long start,

> >  {

> >       struct vm_area_struct *vma;

> >       unsigned long vm_flags;

> > -     int i;

> > +     long i;

> >

> >       /* calculate required read or write permissions.

> >        * If FOLL_FORCE is set, we only require the "MAY" flags.

> > --

> > 2.25.1

>

> --

> Michal Hocko

> SUSE Labs
diff mbox series

Patch

diff --git a/mm/gup.c b/mm/gup.c
index 591d8e2dfc70..1ebb7cc2fbe4 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -1481,7 +1481,7 @@  static long __get_user_pages_locked(struct mm_struct *mm, unsigned long start,
 {
 	struct vm_area_struct *vma;
 	unsigned long vm_flags;
-	int i;
+	long i;
 
 	/* calculate required read or write permissions.
 	 * If FOLL_FORCE is set, we only require the "MAY" flags.